1. Field of the Invention
The present invention relates to the field of magnetic resonance imaging equipment. More precisely, the present invention relates to an audio and video system including a liquid crystal display that is not disrupted by strong magnetic fields created by Magnetic Resonance Imaging devices.
2. Description of the Prior Art and Related Information
Magnetic Resonance Imaging (i.e., "MRI") is a relatively new scanning procedure being used in the medical community extensively. MRI is a valued technique for assisting doctors diagnose numerous medical ailments. The scanning procedure requires that a patient lie still inside a tunnel shaped enclosure called the bore. The MRI device uses a strong magnetic field that is generated around the patient's body. Disturbances in the field due to the presence of the body can be detected and translated into images displayed on a viewing screen.
MRI technology involves very sophisticated hardware. The most prominent piece of hardware is a large magnet that induces a strong, uniform, and static magnetic field. Generally, the magnetic field ranges from 0.5 Tesla to 2.0 Tesla inside the bore. Gradient coils disposed around the bore induce spatially variant magnetic fields (i.e., gradients) that modify the existing uniform magnetic field. To induce nuclear resonance, a transmitter emits radio waves through a coil, which coil couples the radio wave energy with the resonating nuclei inside the magnetic field. A receiver, also connected to the coil, receives the disrupted electromagnetic waves. The waves are filtered, amplified, and processed into visual data for viewing by an MRI technologist attending to the procedure. More detailed information regarding MRI equipment is available in a book entitled Nuclear Magnetic Resonance, pp. 53-66 (1st ed. 1981), the contents of which are incorporated by reference.
As useful as an MRI scanning procedure is, it exacts a toll on the patient. For example, on many occasions patients cannot complete the exam due to claustrophobia caused by having to lie prone inside the bore for a long time while the procedure takes place. To be sure, the procedure is rather long in duration, lasting about half an hour up to two hours. Or, the patient simply gets bored or restless from being in a tight area.
Another discomforting factor is that during the MRI exam there is a harsh and loud knocking noise generated by the MRI gradient amplifier. This noise is commonly called gradient pulse, which naturally is very annoying to the patient who must endure the drone for a long period of time.
Accordingly, there is a great demand for some method of comforting the patient to keep his mind off the MRI scanning procedure. He should be entertained in some way without having the entertainment aspect detracting from the quality of the images that are being taken by the MRI technologist. Indeed, the patient should be relaxed somehow since the MRI device is formidable-looking and the patient is most likely already nervous from having to undergo such an examination.
A quick and simple solution to the entertainment problem is to provide the patient with a television to view, or a radio to listen to. But by virtue of the operating principles behind MRI technology, the exam room where the main magnet is located is permeated with very strong magnetic fields. So it is nearly impossible for a typical television, video cassette recorder (VCR), stereo, cassette player, or any electronic device to function properly in those conditions. In short, the effect of the strong magnetic field and the sensitivity of the MRI hardware to high frequency RF leakage (mainly from 10 MHz to 70 MHz) do not allow an ordinary television or audio system to function inside the magnet room (i.e., exam room).
Therefore, a need presently exists for an electronic device that can operate in the environment of an MRI magnet room to entertain a nervous patient while he or she undergoes the scanning procedure. The electronic device should also not interfere with the MRI process.